1. Field of the Invention
The present invention relates to an apparatus for generating an aroma by volatilizing an aromatic agent or agents.
2. Description of Related Art
Various types of apparatus for generating aroma in a chamber by using one or more volatilizable aromatic agent have been proposed. When such a volatilizable aromatic used in these types of aroma generating apparatus is subjected to volatilization, which takes place naturally, the density of the aroma increases as the time lapses. Contrary to this, a substantial reduction in sensitivity to an aroma will occur upon a lapse of time. A perfume generating device has therefore been proposed where the supply of the aromatic agent is controlled in accordance with time, thereby maintaining a desirable aromatic circumstance in a space for relatively prolonged time. See Japanese Un-Examined Patent Publication No. 2-60821 and Japanese Un-Examined Patent Publication No. 2-225125.
In the perfume generating device in the above mentioned prior arts, it is proposed to use a plurality of different aromatic agents, one of which is usually selected when used. When it is desired, two or more kinds of aromatic agents are mixed for use. In case where such different aromatic agents are used, a unified control of the device has been employed irrespective of the different aromatic natures of the agents. When an aromatic agent, as selected by a user, provides an aroma for providing a relaxing effect, the prolonged use of such aroma can cause the concentration level to fall. Namely, a continuous supply of the aroma providing a relaxing effect in a vehicle or a factory may sometimes be unsuitable from the view point of safety.
In an Un-Examined Japanese Patent Publication No. 4-170964, a three way branched box is provided, which is provided with cassettes for different aromatic agents. A pipe is provided for connecting a downstream end of an air conditioning duct with the three way branched box. Valve units are provided for obtaining a connection of the pipe with the cassettes of different aromatic agents. The valve units controls the amount of the respective odor components, so that a desired rate of mixing of the odor agents supplied to the air conditioning duct is obtained.
In the Japanese Un-Examined Patent Publication No. 58-81817, a container for storing a deodorant agent is arranged outside the air conditioning duct of an air conditioning system for a vehicle. The deodorant container is connected to the air conditioning duct via two pipes. The dynamic pressure in the air conditioning duct, generated by the flow of the air in the duct, is used to generate a flow of the deodorant agent from the container into the air conditioning duct.
In the Un-Examined Japanese Patent Publication No. 4-170964, the odor supply port at the end of the pipe is opened to the air conditioning duct at a location which is downstream from a front outlet damper for selectively opening or closing the front outlet (vent outlet) opened to the cabin for creating a flow of warm air toward lower portion of the cabin during low-level-mode operation. The damper closes the vent outlet at modes other than the low-level mode. In other word, the prior art is defective that a supply of the odor to the cabin is obtained only when the low level mode is selected.
In the Japanese Un-Examined Patent Publication No. 58-81817, the deodorant supply opening at the end of the pipe is opened to the air conditioning duct at a location upstream from a heater core. As a result, an absorption of the deodorant takes place at the heater core, causing the amount of the deodorant supplied to the cabin to be decreased, causing the deodorization efficiency to fall.